© The Institution of Engineering and Technology
MgAl2O4 (MAO)-based magnetic tunnel junctions (MTJs) with an MAO thickness of ∼1.25 nm are fabricated and their cycling characteristics under dynamic voltage stress are evaluated. The speed of breakdown strongly depended on the pulse polarities used, bipolar, positive (+) unipolar, and negative (−) unipolar. The bipolar condition yielded more rapid breakdown under cycling. Between the two unipolar conditions, positive bias yielded more rapid breakdown than negative bias; the difference between these is understood to arise from the conditions of the interface between the MAO and ferromagnetic layers. Among apparently normal MTJ cells showing little resistance drift, 20% were degraded during a long cycling test in the bipolar stress condition. Thus, the use of bipolar voltage stress is essential to screen for potentially defective MTJs, and the asymmetric condition at the interface is minimised by process control for application of the simple unipolar bias condition.
References
-
-
1)
-
3. Dorrance, R., Ren, F., Toriyama, Y., et al: ‘Scalability and design-space analysis of a 1T-1MTJ memory cell for STT-MRAM’, IEEE Trans. Electron Devices, 2012, 59, (4), pp. 878–887 (doi: 10.1109/TED.2011.2182053).
-
2)
-
11. Carboni, R., Ambrogio, S., Chen, W., Siddik, M., Harms, J., Lyle, A., Kula, W., Sandhu, G., Ielmini, D.: ‘Understanding cycling endurance in perpendicular spin-transfer torque (p-STT) magnetic memory’. IEDM, San Francisco, USA, 2016, pp. 572–575, .
-
3)
-
2. Chen, E., Apalkov, D., Diao, Z., et al: ‘Advances and future prospects of spin-transfer torque random access memory’, IEEE Trans. Magn., 2010, 46, (46), pp. 1873–1878 (doi: 10.1109/TMAG.2010.2042041).
-
4)
-
5. Sukegawa, H., Xiu, H., Ohkubo, T., Furubayashi, T., Niizeki, T., Wang, W., Kasai, S., Mitani, S., Inomata, K., Hono, K.: ‘Tunnel magnetoresistance with improved bias voltage dependence in lattice-matched Fe/spinel MgAl2O4/Fe(001) junctions’, Appl. Phys. Lett., 2010, 96, pp. 212505-1–212505-3, .
-
5)
-
1. Hosomi, M., Yamagishi, H., Yamamoto, T., Bessho, K., Higo, Y., Yamane, K., Yamada, H., Shoji, M., Hachino, H., Fukumoto, C., Nagao, H., Kano, H.: ‘A novel non-volatile memory with spin torque transfer magnetization switching: spin-RAM’. IEDM Technical Digest, Washington, DC, USA, 2005, pp. 459–462, .
-
6)
-
9. Choi, C.M., Sukegawa, H., Mitani, S., Song, Y.H.: ‘Effect on Mg insertion on time-dependent dielectric breakdown in MgO-based magnetic tunnel junctions’, Electron. Lett., 2016, 52, pp. 1037–1039 (doi: 10.1049/el.2016.0686).
-
7)
-
4. Hosotani, K., Nagamine, M., Aikawa, H., Shimomura, N., Nakayama, M., Kai, T., Ikegawa, S., Asao, Y., Yoda, H., Nitayama, A.: ‘Resistance drift of MgO magnetic tunnel junctions by trapping and degradation of coherent tunneling’. IEEE Int. Reliability Physics Symp., Phoenix, Arizona, USA, 2008, pp. 703–704, .
-
8)
-
8. Amara-Dababi, S., Sousa, R.C., Chshiev, M., Béa, H., Alvarea-Hérault, J., Lombard, L., Prejbeany, I.L., Mackay, K., Dieny, B.: ‘Charge trapping–detrapping mechanism of barrier breakdown in MgO magnetic tunnel junctions’, Appl. Phys. Lett., 2011, 99, pp. 083501-1–083501-3 (doi: 10.1063/1.3615654).
-
9)
-
11. Sukegawa, H., Mitani, S., Ohkubo, T., Inomata, K., Hono, K.: ‘Low-resistive monocrystalline Mg-Al-O barrier magnetic tunnel junctions for spin-transfer magnetization switching’, Appl. Phys. Lett., 2013, 103, pp. 142409-1–142409-5 (doi: 10.1063/1.4824134).
-
10)
-
7. Choi, C.M., Oh, Y.T., Lee, J.Y., Sukegawa, H., Mitani, S., Song, Y.H.: ‘Effect of Mg insertion on stress-induced resistance drift in MgO-based magnetic tunnel junctions’, Electron. Lett., 2016, 52, pp. 531–533 (doi: 10.1049/el.2015.4299).
-
11)
-
10. Sukegawa, H., Inomata, K., Mitani, S.: ‘Post-oxidized Mg-Al-O(001) coherent tunneling barrier in a wide range of resistance-area products’, Appl. Phys. Lett., 2014, 105, pp. 092403-1–092403-3, (doi: 10.1063/1.4895104).
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